The present invention relates to an inkjet recording head which uses, as a pressure generating source, piezoelectric vibration elements of the longitudinal vibration type, which are each constructed such that a plurality of internal electrodes are alternately layered in a state that piezoelectric material is interposed therebetween.
The inkjet recording head, which uses the piezoelectric vibration elements each vibrating in the longitudinal vibration mode, includes a plurality of linear arrays each consisting of pressure generating chambers, each chamber communicating with a nozzle orifice and a part of each chamber being sealingly closed with an elastically deformable plate member. Each pressure generating chamber is expanded and contracted by its associated piezoelectric vibration element which axially deflects in accordance with a drive signal applied thereto.
The piezoelectric vibration elements are constructed as a unit form as shown in FIG. 15. That is, a piezoelectric vibrating plate, which is wide enough to cover a plurality of piezoelectric vibration elements, is fastened to a fixing plate 60, and is cut into a plurality of piezoelectric vibration elements 61 with a wire saw or the like to be arranged at a constant pitch.
Dummy piezoelectric vibration elements 62 and 63, which are not associated with the ink drop ejecting operation, are provided at both ends of a linear array of piezoelectric vibration elements in order to improve the workability in positioning the piezoelectric vibration elements in the stage of assembling. In assembling the piezoelectric vibration elements, the outer side surfaces 62′ and 63′ of the dummy piezoelectric vibration elements 62 and 63 are used as a reference in setting the piezoelectric vibration element unit to a case, whereby the piezoelectric vibration elements 61 are positioned with respect to the fluid channel unit within a predetermined tolerance.
The piezoelectric vibrating plate is formed such that internal electrode material layers including metal and piezoelectric material layers are layered, and the resultant layered structure is sintered. The cutting of the thus formed piezoelectric vibrating plate with a wire saw into a plurality of piezoelectric vibration elements will minutely shift the actual cutting lines from the correct cutting lines since the internal electrodes are hard. The shift of the cutting lines greatly affects an accuracy of the relative positioning of the piezoelectric vibration element unit when the distal ends of the piezoelectric vibration elements are reduced in area for the purpose of increasing a print density.